Formed half coil for the excitation of rotating field magnets



Mafch 6, 1934. F. PUNGA ET AL 1,950,268

FORMED HALF COIL FOR THE EX ITATION 0F ROTATING FIELD MAGNETS Filed Nov.20, 1930 35 that is with slots machined out.

Patented Mar. 6, 1934 FORMED HALF COIL FUR THE EXCITATION PF ROTATINGFIELD MAGNETS Franklin Funga, Vilienkolonie Eberstadt, near Darmstadt,and Herman Boos, Allensbach cnthe-Eodensee, Germany Application November20, 1930, Serial No. 496,954 In Germany November 22, 1929 @laims.

In the known construction of dynamo electric machines having high speedfield magnets with subdivided windings and teeth on the magnet bodywhich hold the windings, the windings must 5 be inserted turn by turninto the radial slots;

the deeper the slots the more difiicult the insertion of the individualturns.

Ingenious and expensive constructions have been used in which theprojections or teeth which hinder the insertion of the windings are setinto dovetail slots in the magnet body only when or after the coils areinserted. With this construction, form wound, insulated, pressed coilscan be used. The great advantages of such coils lie not only in thepossibility of separately making them and reliably insulating them, butin the far more satisfactory cooling conditions which are given by thepressing on of the outer insulation and avoidance of air cells, by thepossibility of reducing the thickness of the outer insulation andcombining it with the intermediate insulation or with suitablearrangement of air conduits in the slots and entirely omitting the outerinsulation. ihese conditions enable the current density of the copperand correspondingly the output of the machine to be considerablyincreased so that expense involved in making the insertabl inductorteeth and the necessity for having a large number of various complicatedand ex- 0 pensive coil presses available is justified.

The present invention has for its object to make such pressed and easilycooled coils usable With the much simpler and cheaper inductorconstruction with integral teeth on the magnet body,

lhis is possible with so-called form wound half coils.

A further object of the invention is to provide an arrangement for theconnection of the halves of the split coils so that they may becompletely accessible and freely accommodate them in the shortest coilends measured circumferentially, and at the same time resulting in asuperior cooling of the conductors.

With these and other objects in View, the invention can be more easilyunderstood by reference to the accompanying drawing:

Fig. 1 is a diagrammatic illustration showing the manner of connectionof the conductors at the ends of the coil;

Fig. 2 is a side elevational View of a plurality of conductors at theend of the coil and the manner in which they are connected;

Fig. 3 is a right sectional View of Fig. 2;

V Fig. 4 is a plan View of Fig. 2;

Fig. 5 is a perspective view showing in detail the manner of connectingthe conductors;

6 is a perspective view showing the top and bottom halves of theconductor coils, spaced apart prior to their connection; 63

Fig. 7 is a sectional view of a modified form of connection;

Fig. 8 is a plan view showing the manner of connecting the ends oiconductors when lying in two parallel groups;

Fig, 9 is a perspective view of three superposed independently twistedgroups of coils;

Fi 10 is a side elevational view of the coil shown in Fig. 9.

In the figures, a refers to the conductors of the left hand side of thecoil, 1) the conductors of the right hand side oi: the coil, and c thetransposition or connecting pieces.

With what may be termed twisted bars, the individual conductors a and bare brought out of the superposed conductors and carried upward ordownward past the other conductors, so here to achieve the desiredobject, the individual conductors of the field magnet coils are piledone on top of another, stepped and bound. The division of the two halvesis effected at any "esired suitable position, preferably in free lyingpolar arcs; transposition or connection pieces can be arranged inrecessed slots as in the Funga- Roos twisted bar Patent No. l,4=78,252but preferably at a certain spacing from the superposed conductors.Thereby not only is space obtained for soldering or welding and the coilll'lSl. ation protected from damage but very effective cool ing surfacesare formed, since each individual conductor is directly swept by thecooling air on all sides over a portion spaced from the pile ofconductors.

The connecting pieces 0, as shown in Fig. 6, are first turned edgewisethrough 90, then bent i'iatwise from the dotted line to the full linepositions shown in the drawing and then soldered or welded together,either butted as in Fig. 3 or overlapping as in Fig. '7. In the lattercase, to protect them against mechanical stresses, the overlapping canbe so arranged that the end of one piece rests against the base of theother.

If a large number of conductors lie on one another then there is nospace available in the cii'cinnierentlally shortestcoil end of the coilnearest the pole, to accommodate the transposition or connecting pie"esside by side. This difficulty is avoided, as shown in Fig. 9, bydividing the superposed conductors a and 1) into two or more groupswhich are separately twisted, that, is, divided, layered and connectedas shown. With, for instance 24 superposed conductors, by dividing theminto two groups there are only 12 neighboring transposition orconnection pieces in each group, and with three groups only 8, so thatthe lack of peripheral space is entirely overcome. Corresponding withthe subdivision into two or three groups, there are two or threesuperposed rows of transposition or connection pieces 0. Since withcoils having long ends subdivision into groups may not be necessary,subdivided and unsubdivided coils may be used on one and the sameinductor. For clearness, the corresponding connecting pieces of thethree groups are shown relatively staggered, but it may be desirable tosuperpose them for support against centrifugal force.

In Fig. 8 another mode of construction in which the freeing, dividingand joining of the connecting pieces 0 are eflected in the intermediatespace between two parallel groups of conductors, and the connectingpieces all lying accessible at the top of the coil.

Whereas complete coils are limited by the capabilities of the windingmachine, it is possible with form wound half coils to shape theindividual conductors of the half coils as desired before insulation, asmay be required by the position, support and cooling in the slot orunder the end cap, by the dimensions of the end cap itself, or by thearrangement and formation, for example of the damping winding. The coilwinding machine can be replaced by simple bending devices,

the size of the coil presses is reduced by a half and if only thelongitudinal sides are pressed,

only a single, simple longitudinal press per inductor is necessary.

What we claim is:

1. A high speed rotor coil split along the axis of the rotor in whicheach half of the said coil comprises a plurality of superposedconductors, the ends of the said halves being connected to each other atthe end of the rotor and at the outside of and spaced from thesaidsuperposed layer of conductors.

2. A high speed rotor coil split along the axis of the rotor in whicheach half of the said coil comprises a plurality of superposedconductors, the ends of the said halves being connected to each other atthe end of the rotor the ends of the conductors being so stepped andinclined that each conductor half from its top position may be connectedto the opposite half positioned at the bottom and the connections beinglocated at the outside of the superposed conductors.

3. A high speed rotor coil as defined by claim 1 in which the halves ofthe coils are stepped and oiiset in such a manner that the conductorwhen it is in the uppermost position of one of the halves is connectedto the corresponding uppermost conductor of the other half.

4. A high speed rotor coil as defined by claim 1 in which the coil issubdivided-into a plurality of separately interconnected groups.

5. A high speed rotor coil as defined by claim 1 in which the cojoiningends of the individual conductors are bent outwardly away from the coiland toward each other, to present ends ready for connection.

HERMANN ROOS. FRANKLIN PUNGA.

